The present invention relates to synthetic seaweed, and more particularly to such seaweed for use in building an underwater reef whose purpose is to inhibit coastal erosion.
Prior to the present invention, artificial seaweed constructions have been proposed for combatting coastal erosion. For example, U.S. Pat. No. 3,299,640, granted Jan. 24, 1967, describes a seaweed type structure for influencing the sub-marine migration of material. This structure consists of a screen formed by a large series of filamentary plastic strands secured at one end to an anchoring device placed at the bottom of the sea. The strands are buoyant and therefore assume and retain an upright position thereby reducing currents in the surrounding water while promoting the deposition of sand and other solid materials entrained by the water. Also shown in the above patent is a group of individual spaced apart buoyant tapes secured to a rope-like anchor. In each instance the function of these constructions is to combat coastal erosion.
U.S. Pat. Nos. 3,559,407 and 3,590,585, granted Feb. 2, 1971 and July 6, 1971, respectively, also disclose artificial seaweed wherein assemblages of filamentary strands of foamed, stretched polyolefin are used for influencing the migration of material at the bottom of bodies of water, as in combatting coastal erosion. Entanglement of the filamentary strands is troublesome during manufacture, installation and use, and U.S. Pat. No. 3,590,585 discusses several approaches to prevent such entanglement.
Obviously, it is important that once any artificial seaweed construction is installed, such construction functions to promote sedimentation of solid particles. It is therefore desirable that the seaweed be sufficiently strong to withstand ocean forces and also particularly designed so that the majority of filamentary strands or tapes remain free of entanglement.